Blue azo wool dye and process of making same.



UNITED STATES PATENT OFFICE.

AUGUST LEOPOLD LASKA, ()F OFFENBACH-ON-THE-MAIN, GERMANY,

ASSIGNOR TO THE FIRM OF K. OEHLER, ANILIN & ANILINFARBEN- FABRIK, OF OFFENBACH-ON-THE-MAIN, GERMANY.

BLUE AZO WOOL DYE AND PROCESS OF MAKING SAME.

Specification of Letters Patent.

Patented Sept. 5, 1905.

Application filed April 13, 1905. Serial No. 265,473. (Specimens) To all lull/07121 it Trmy concern:

Be it known that 1, AUGUST LEOPOLD LASKA, doctor of philosophy, chemist, residing at 5 (JiBIlJQISllI'flSSG, ()fl'enbach-on-the-lViain, in the Grand Duchy of Hesse, Germany, have invented certain new and useful Improvements in Azo Dyes for Tool, of which the following is a specification.

My invention relates to the production of a new dyestuff by combining the diazotized 6- nitro-Q-amidophenol-a-sulfonic acid with betaoxynaphtoic acid of the fusing-point of 216 centigrade.

The new dyestulf yields on wool, even when dyed in a proportion of only two per cent., an indigo blue which is of a particular value be cause of its greenish shade and its brightness when looking over the hand.

In the following example I shall illustrate the nature of my invention and how it may be carried out: Sixty-four parts of 6nitro-2- amido-phenol-L-sulfonic acid (sodium salt) are dissolved in water and diazotized by means of one hundred and ten parts of hydrochloric acid of Baum and 17.5 parts of sodium nitrite at about 10 centigrade. The diazo solution is poured into a cold solution of fifty parts of beta-oxynaphtoic acid of the fusingpoint of 216 centigrade, nine hundred parts of water, and forty parts of sodium lye, Baum, to which seventy-five parts of soda have been added. After the combination is completed the whole is heated up to 70 cen- -tigrade and the dyestufl' then precipitated by adding common salt and some hydrochloric acid. After drying it represents a blackbrown powder dissolving in water to a violet solution and in concentrated sulfuric acid to a bluish-red one. On adding hydrochloric acid the aqueous solution turns into a yellowisla red, whereas sodium lye it renders bluish re Besides its beautiful shade, the new dyestuff is distinguished by the valuable property that it leaves the cotton-effect threads absolutely undyed and that its shade is not altered by artificial light.

Now what 1 claim, and desire to secure by Letters Patent, is the following:

1. The process of producing an azo dye for W001, consisting in combining diazotized 6- nitro-Q.amidophenollsulfonic acid with beta-oxynaphtoic acid of the fusing-point of 216 Centigrade.

2. As a new article the coloring-matter, which results from the combination of diazotized 6 nitro Q-amidophenol-af-sul fonic acid with beta-oxynaphtoic acid of the fusing-point of 216 centigrade, the alkali salt of which forms a blackish-brown powder, dissolves in concentrated sulfuric acid to a bluish red in water to a violet solution, turning into a yellowish red on adding hydrochloric acid, while simultaneously separating the dyestufl' as a fiocky precipitate, and being rendered bluish red by sodium lye, all substantially as hereinbefore described.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two witnesses, this 31st day of March, 1905.

AUGUST LEOPOLD LASKA.

WVitnesses:

HEINRICH NEUENHAUS, HERMAN WVEIL. 

